Plywood Over Plank Roof

Personally i like plank spaced decking.

Plywood over plank roof.

In the first half of the 20th century roofs in missouri were built with wood shingles over planks spaced about 1 apart. Over time shiplap fir wood resin dissipates causing the boards to shrink crack form knot holes and become extremely brittle. Plywood is layers of wood plywood is made. In that case they could whe replacing shingles fill the larger gaps with firring.

On older homes planks were often spaced for wood or slate roofs with wider exposures than the standard 5 inch tab on asphalt shingles. It was common practice to have a clause in the contract that once the roof was stripped down depending on what was found plank roofs that were not already covered with plywood would then need to be covered in order to do a good job and provide a solid warranty. Or they could place osb or plywood over current planking. Open spaces form between the once tightly fitted shiplap boards.

These 8 to 12 inch wide boards were nailed together tight. But the spacing should not be more than quarter inch. Use door skins to raise dips to 1 8 use contact cement to secure to existing 1 4 ply secure 17 32 plywood to the planks with 1 5 deck screws avoiding the joists to allow slip install engineered hardwood over the new subfloor w underlayment if needed. Repair any broken planks.

Things to take into account when laying ply over plank subfloors. This is particularly important if your old sub floor has lumps and bumps in it. We resheet with 1 2 osb right over top of the old all the time be it 3 8 ply or old t g boards in the case of the old t g boards it makes for a flatter surface plus greatly lessons the chance of nailing into the gap between boards. Plywood used for roof decking is typically called sheathing and carries a grade stamp indicating its load and span ratings and other performance factors.

Most western washington residential homes during this time were built with shiplap roof decks rather than plywood. Take time to make sure your existing planks are well secured in place. Plank sheathing usually 1 6 or 1 8 was used as a roof deck before plywood. Why re sheet over shiplap.

Today a shiplap roof is usually 60 years old. Use decking screws to secure squeaking planks through 1 4 ply to joists. As roofing contractors in seattle we are often asked why do we need plywood over our old solid sheathing. The plank problem typically sheathing problems are isolated to small areas but old plank sheathing presents more of a challenge.

Install a layer of at least or preferably 5 8 ply over the existing planks. Its really common here too to see 3 8 plywood used on roofs from the 70 s.